The idea is that miners have to hold their coins for a set amount of time. When they hold their coins it will be in their best interest to promote the coin, create services, ..., thus increasing its value. Even miners who mine to immediately dump will be forced to hold and promote if they are mining directly.
Of course there are some miners who will want to have their coins immediately I foresee pools like blackcoinpool to mine other coins and buy vested Futurecoins on the open market and pay out their miners immediately. This also good because it creates buy support.
Just to clarify, IPO'ers are not bound by vesting, and can basically pump and dump (in a worth case scenario) as they wish?
IPO coins are distributed according to the phase.
Phase 1 - 1 week block maturity - From 4/10 - 4/18
Phase 2 - 2 week block maturity (on par with mined coins) - From 4/19 - 4/25
Phase 3 - 3 week block maturity - From 4/26 - 5/2
Nothing of course can prevent investors from dumping, but I believe that this should at least give the market enough time to build support so that a dump will not affect price too much.